chore: revert OPA bump to unblock stackabletech/docker-images#969

Author: dervoeti

tests/test-definition.yaml

@@ -31,7 +31,7 @@ dimensions:
       - 3.9.2
   - name: opa
     values:
-      - 1.0.0
+      - 0.66.0
   - name: hadoop
     values:
       - 3.4.0